1. Field of the Invention
The present invention relates generally to a computer implemented method, data processing system, and computer program product for managing a distributed database. More specifically, the present invention relates to responding to domain name service queries and purging a domain name service database of resource records as needed.
2. Description of the Related Art
When computers were first networked together many decades ago, each computer was assigned numeric addresses to identify uniquely to which computer a packet was addressed. Since then, a number of advances have made computers and other networking equipment easier to identify, especially to people. In particular, many server computers have been provided a host name or domain name by which the computers may conveniently be addressed in accordance with a mnemonic scheme established by the creator of the server. Such a mnemonic scheme permits a domain owner to announce and advertise the availability of services on its computer or computers in simple domain names or hostnames, for example, ibm.com or illinois.edu. A hostname refers to a domain name that has one or more associated IP addresses. For example, the ‘www.example.com’ and ‘example.com’ domains are both hostnames, however, the ‘com’ domain is not. A domain name is a sequence of labels separated by dots, for example, ‘.’. The labels may be established by a centralized naming authority such as, Internet Corporation for Assigned Names and Numbers (ICANN) or its delegates.
The above system using handy names has been preferred in conversation, man-machine interaction, and other processes involving people, as compared to the more cumbersome Internet Protocol Version 4 (IPv4) address of the form, for example, 192.168.0.1. The IPv4 and newer IPv6 both provide IP addresses to an organization that are comprised of numbers, and typically, in batches that are assigned in series. Accordingly, this scheme can be more cumbersome for people to remember the address associated with an organization. Fortunately, the domain name system is a world-wide distributed database that permits an association between the internet protocol (IP) address and the corresponding domain name.
Organizations can change the IP address that services a domain. Such changes make older IP address to domain name associations obsolete. A system created to purge obsolete or otherwise expired IP address to domain associations from the domain name service (DNS) system is desirable.